KASAN: vmalloc-out-of-bounds Read in get_counters

From: syzbot
Date: Wed Jul 29 2020 - 04:20:19 EST


Hello,

syzbot found the following issue on:

HEAD commit: 68845a55 Merge branch 'akpm' into master (patches from And..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13668964900000
kernel config: https://syzkaller.appspot.com/x/.config?x=f87a5e4232fdb267
dashboard link: https://syzkaller.appspot.com/bug?extid=a450cb4aa95912e62487
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a450cb4aa95912e62487@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in get_counters+0x593/0x610 net/ipv6/netfilter/ip6_tables.c:780
Read of size 8 at addr ffffc9000528b048 by task syz-executor.1/6968

CPU: 1 PID: 6968 Comm: syz-executor.1 Not tainted 5.8.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0x5/0x436 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
get_counters+0x593/0x610 net/ipv6/netfilter/ip6_tables.c:780
do_ip6t_get_ctl+0x516/0x910 net/ipv6/netfilter/ip6_tables.c:821
nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
nf_getsockopt+0x72/0xd0 net/netfilter/nf_sockopt.c:122
ipv6_getsockopt+0x1bf/0x270 net/ipv6/ipv6_sockglue.c:1468
tcp_getsockopt+0x86/0xd0 net/ipv4/tcp.c:3893
__sys_getsockopt+0x14b/0x2e0 net/socket.c:2172
__do_sys_getsockopt net/socket.c:2187 [inline]
__se_sys_getsockopt net/socket.c:2184 [inline]
__x64_sys_getsockopt+0xba/0x150 net/socket.c:2184
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ee7a
Code: Bad RIP value.
RSP: 002b:0000000000c9f618 EFLAGS: 00000212 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 0000000000c9f640 RCX: 000000000045ee7a
RDX: 0000000000000041 RSI: 0000000000000029 RDI: 0000000000000003
RBP: 0000000000744ca0 R08: 0000000000c9f63c R09: 0000000000004000
R10: 0000000000c9f740 R11: 0000000000000212 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000029 R15: 00000000007445e0


Memory state around the buggy address:
ffffc9000528af00: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
ffffc9000528af80: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
>ffffc9000528b000: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 f9 f9
^
ffffc9000528b080: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
ffffc9000528b100: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.